This invention relates generally to load responsive fluid control valves and to fluid power systems incorporating such valves, which systems are supplied by a single fixed or variable displacement pump, provided with a load responsive output flow control. Such control valves are equipped with an automatic load responsive control and can be used in a multiple load system, in which a plurality of loads is individually controlled under positive load conditions by separate control valves.
In more particular aspects this invention relates to a load responsive system using a load responsive pump control and load responsive individually compensated direction control valves, for control of positive loads, in which the controlled pressure differential, both of the load responsive pump control and load responsive valve controls, can be varied in response to external control signals.
Load responsive systems using load responsive pump control and individually compensated load responsive direction control valves are very desirable, since they provide high system efficiency, while permitting simultaneous proportional control of multiple positive loads. So far those systems have been based, both for the load responsive pump control and load responsive valve controls, on the principle of the constant pressure differential maintained across a controlling orifice. This principle, although effective, reduces to a degree system efficiency and the flexibility of the control.